"여자아이는 남자에게서 개를 받습니다."
Translation:The girl gets a dog from the man.
Actually a Korean woman I know told me 'girl' is 소녀 and 'boy' is 소년, I don't know why Duo uses 남자아이 and 여자아이, although technically those could be considered correct? I dknt really know if those are actually used much in Korean but from what I've seen they usually say 소녀 and 소년
Talk to me in Korean explains this very well and in great detail in their Level 1, Lesson 4 podcast. In summary because of the natural moment of the mouth, sounds that are aspirants (p, d, etc) get changed to an M sound. so Hap-ni-da is changed to Ham-ni-da (no Korean keyboard here sorry).